Components of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jan. 31, 2018	Jul. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Cost	$ 572,327	$ 572,327
Accumulated Amortization	$ 156,215	128,861
Dealer Network/Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	16 years
Cost	$ 404,960	404,960
Accumulated Amortization	$ 124,519	101,795
Trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	18 years
Cost	$ 147,617	147,617
Accumulated Amortization	$ 21,434	17,570
Design Technology and Other Intangibles
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	8 years
Cost	$ 19,300	19,300
Accumulated Amortization	$ 9,925	9,203
Non-Compete Agreements
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	1 year
Cost	$ 450	450
Accumulated Amortization	$ 337	$ 293